What is 5.1, 7.1 surround sound?

[Richie Nieto]

Actually, 7.1 is Left, Left Center, Center, Right Center, Right, Left Surround, Right Surround and Boom (Subwoofer) channels. The advantage over 5.1 is that you get a more precise placement of sound across the screen.
THX is not a format but a standard of equipment and room characteristics devised by Tomlinson Holman (Xperiment, thus, "THX").
The additional rear channel is part of the Dolby Digital-Surround EX system, which was developed by Dolby Laboratories and Lucasfilm THX. It plays off 5.1 format but requires an adaptor to split the surround signals.

Regards!

[Noiz2]

You gotit
Where they get used is 5.1 is the dolby digital standard and 7.1 is the SDDS standard. which is why PT users in postproduction would be interested in both.

I attended the Pro Tools demo last night in Atlanta. Ok, so I'm an amateur, bur what exactly is "5.1" surround? 2 main, 2 rear, a center and a sub (as the .1)? What is 7.1 then?

I'm just trying to start to understand.

Thanks,
RC

[macguy]

RC,

As I understand it 7.1 is as follows:

1 center, 2 front, 2 sides L & R, 2 rear and 1 sub.

There also is a newer concept or addition. It has been awhile since I read about it but I believe it is called THX LE. It gives you a rear speaker, goes inbetween your two rear speakers. It give you a more realistic "Movie Theater Experience". It was an other great idea from the guys at Skywalker Ranch..i.e. Gary R.

Anyway....there you have it.

Any correctins or additions are appreciated.

Macguy

[Richie Nieto]

5.1 is also utilized by DTS, which plays off a CD ROM synced to picture via timecode printed on the film.
All three main digital formats use optical (analog) tracks on the film as backup, in case of dropouts.

[zackelly]

I'd love to have a speaker mounted on the roof so a bomb, or Stuka Dive bomber, or even a wanky guitar solo can come falling from the heavens.